diff options
| -rw-r--r-- | arch/s390/mm/fault.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index d814f7914003..6903d441068e 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -567,6 +567,7 @@ static void pfault_interrupt(unsigned int ext_int_code, tsk->thread.pfault_wait = 0; list_del(&tsk->thread.list); wake_up_process(tsk); + put_task_struct(tsk); } else { /* Completion interrupt was faster than initial * interrupt. Set pfault_wait to -1 so the initial @@ -576,14 +577,22 @@ static void pfault_interrupt(unsigned int ext_int_code, put_task_struct(tsk); } else { /* signal bit not set -> a real page is missing. */ - if (tsk->thread.pfault_wait == -1) { + if (tsk->thread.pfault_wait == 1) { + /* Already on the list with a reference: put to sleep */ + set_task_state(tsk, TASK_UNINTERRUPTIBLE); + set_tsk_need_resched(tsk); + } else if (tsk->thread.pfault_wait == -1) { /* Completion interrupt was faster than the initial * interrupt (pfault_wait == -1). Set pfault_wait * back to zero and exit. */ tsk->thread.pfault_wait = 0; } else { /* Initial interrupt arrived before completion - * interrupt. Let the task sleep. */ + * interrupt. Let the task sleep. + * An extra task reference is needed since a different + * cpu may set the task state to TASK_RUNNING again + * before the scheduler is reached. */ + get_task_struct(tsk); tsk->thread.pfault_wait = 1; list_add(&tsk->thread.list, &pfault_list); set_task_state(tsk, TASK_UNINTERRUPTIBLE); @@ -608,6 +617,7 @@ static int __cpuinit pfault_cpu_notify(struct notifier_block *self, list_del(&thread->list); tsk = container_of(thread, struct task_struct, thread); wake_up_process(tsk); + put_task_struct(tsk); } spin_unlock_irq(&pfault_lock); break; |